@t3p3tony Yes, I think a laser sensor would be the best choice, and Yes 0.3mm is nothing, I'm using a 5mm nozzle and 4 mm layer height.

@fcwilt Thanks, appreciate your help.

Thank you everyone I really appreciate your help.

@t3p3tony Yes, I think a laser sensor would be the best choice, and Yes 0.3mm is nothing, I'm using a 5mm nozzle and 4 mm layer height.

@oliof I don't know if the piezo sensor would work with an ABS sheet laminated to an MDF Board they are very heavy.
I don't want to spend this much on an Ultrasonic sensor It will be better to go with a laser one.

@fcwilt Sounds complicated

@fcwilt I tried that but the long-distance make it hard to mount and to keep straight, also I'm looking for something off the shelf so it will be easy to replace in the future.

@fcwilt No, the plan was to use ultrasonic or laser but the problem is I don't have any experience with both of them and because I'm using an ABS sheet for bed surface I can't use an inductive sensor.
What you suggested might work but I don't know how good it will be with high temperature, it can get to 80C inside the printer.

@fcwilt The Pulsar is over 300mm long and I don't want to mount the sensor to the tool, instead I would like to use the Pulsar mounting bracket to hold the sensor.

@dc42 It needs to be accurate enough for Homing the Printer and for Bed Leveling. The printer size is 2200X1250X1250mm and I'm using a Pulsar Pellet extruder so I need a sensor with a long sensing distance. Is there a Duet sensor that can do this job, or if you can recommend something that will work well with my Duet 3 6HC Board? Thank you.

@fcwiltyou are absolutely right, I didn't notice that detail until you brought it to my attention. Thanks a lot.